The invention relates to electron beam therapy and equipment used for it.
In electron beam therapy, a beam of electrons is directed to a treatment site. Typically, this is brought about using a relatively large electron accelerator unit. This apparatus includes a source of an electron beam, to which is mechanically attached an electron applicator. (The term "electron applicator", as used herein, includes cones and other compensating members and generally encompasses all devices which are placed on or in close proximity to a patient to finally direct the electron beam to the desired treatment site.)
It is now desired to carry out electron beam therapy in an intra-operative environment, i.e. inside the body of a patient through an incision in the patient's skin. This is unfeasable with conventional electron accelerator units.
One reason for this is that the electron accelerator unit is large and unwieldy. It is dangerous to move the electron applicator of such a unit within a relatively small operative incision without risking injury to the patient.
Another reason why intra-operative electron beam therapy is now unfeasable results from governmental and medical regulations which apply to the conduct of intra-operative procedures. These regulations provide that no patient may be subjected during an operation to ground leakage currents which exceed, e.g., five microamperes. This is because (1) blood and body fluids are good electrolytes and excessive current flow can injure a patient and (2) other apparatus (such as that used to monitor the patient's body functions) may be disturbed by excessive current flows. Since ground leakage currents exceeding five microamperes may flow between the patient and a conventional accelerator unit as a result of contact between the electron applicator and the patient's body, such conventional equipment is unsuitable for intra-operative therapy.
It would be advantageous to provide an electron accelerator unit which is suitable for intra-operative use.
One object of the invention is to provide an electron accelerator unit which can be used for electron beam therapy in an intra-operative environment.
Another object is to provide such a unit which is easily mechanically maneuverable with respect to the patient.
Yet another object is to provide such a unit in which there is no possibility of current flow between the unit and the patient.
A further object is to provide such a unit in which an operator cab view the treatment site directly, without using television equipment.
Still a further object is to provide a unit which is easy to use and cost-effective.
Still a further object is to generally improve over the prior art.